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Ignacio Serrano-Pedraza, Sandra Arranz-Paraíso, Verónica Romero-Ferreiro, Jenny Read, Holly Bridge; Short-term monocular deprivation reduces inter ocular surround suppression. Journal of Vision 2015;15(12):379. doi: https://doi.org/10.1167/15.12.379.
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© ARVO (1962-2015); The Authors (2016-present)
The detection of a grating located in the periphery is impaired by the presence of a surrounding grating of same spatial frequency and orientation. This suppression is the psychophysical counterpart of the surround suppression found in the striate cortex that is orientation tuned and can be mediated dichoptically (De Angelis, et al 1994). The proposed sources of this suppression involve long-range lateral connections and feedback connections to V1 from extrastriate cortex, thus the neurotransmitter GABA may regulate this intracortical inhibition. A recent study (Lunghi, et al, 2014) has shown that a short-term monocular deprivation reduced GABA concentration by 11%, thus, our hypothesis is that monocular deprivation will reduce surround suppression. Four subjects performed two contrast-detection experiments where the target was a 1c/deg grating located at 5 deg eccentricity. We tested three conditions: a) target with no surround (NS), b) target embedded within a surrounding grating of 20 deg diameter, 25% contrast, same spatial frequency, and orthogonal orientation (OS), and c) target embedded within a surrounding grating with parallel orientation (PS). We tested both eyes independently using a 3D display. In the first experiment stimuli were monocular. In the second, stimuli were dichoptic, i.e. target in one eye and surround in the other. Both experiments had three sessions; (1) baseline, (2) after 150 min of patching the right eye and (3) 24 hours later. Monocular deprivation did not change the relative contrast sensitivity of the two eyes (Exp 1, NS). Neither did it cause significant differences in suppression indices monocularly (Exp 1, log10(PS/NS)). However, after deprivation, we found a strong, temporary reduction (-41%) of the suppression in the PS condition only when the target was presented in the deprived eye. Thus, brief (2.5hrs) monocular deprivation reduces inter ocular surround suppression but not monocular surround suppression.
Meeting abstract presented at VSS 2015
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